Red-shirt co-leader Nattawut Saikuar has dismissed as premature the idea of the two largest political parties joining hands against the selection of an outsider as the prime minister after the election.
Mr Nattawut said on Monday the possibility of the Democrat and Pheu Thai parties working together to prevent the selection of a non-elected prime minister was only in its infancy.
The idea was mooted at a political forum on Sunday by deputy Democrat leader Nipit Intarasombat and Pheu Thai key figure Chaturon Chaisaeng did not rule it out.
Mr Nattawut, however, said it was only individual opinions and was by no means an official stance of the two parties.
As new polls could be held in November next year at the latest, the United Front for Democracy against Dictatorship frontman said Pheu Thai, the Democrats and other parties should make it clear whether they would accept or oppose an outsider as the prime minister before then.
Under the 2017 constitution, people elect 500 MPs for the House but the prime minister is chosen by a majority vote of both houses. Since the 250 senators are appointed or screened by the junta in the first five years, a party would need at least 376 votes to ensure one of their candidates win, a near-impossibility considering the most recent vote results.
In the latest successful general election in 2011, Pheu Thai led with 265 of all 500 MPs, followed by the Democrat party (159) and Bhumjaithai (34). The turnout rate was 75%.
Given the numbers, the only chance for parties to block a non-MP as the prime minister is for the two largest parties to join hands and agree to vote for one of their candidates as the premier.